The age at which diastolic blood pressure begins to fall occurs much earlier than indicated by Framingham.
01.02 - Hypertension (Prevention & Epidemiology)
Not Member of EACPR
DW. Armstrong1, D. Brouillard1, M. Matangi1 - (1) Kingston Heart Clinic, Kingston, Canada
Purpose. The Framingham data regarding the change in blood pressure with age indicates a progressive and linear increase in systolic BP with advancing age. The change in diastolic BP with age is quite different. The diastolic BP gradually increases until age 55 years and then progressively falls in a curvilinear manner. The purpose of our investigation was to see if this data could be reproduced in the current era. Methods. Our cardiology database was searched for all 24hr ambulatory BP monitors (ABPM). A scattergram of age versus both systolic and diastolic BP was produced for 18,987 ABPMs. Linear regression was performed for the systolic BP data points and 2nd to 4th order polynomial regression was performed for the diastolic BP data points. The inflection point was calculated using differential calculus. This is the point on the diastolic polynomial regression curve where the curvature sign changes. This inflection point corresponds to the age at which diastolic BP begins to decrease. Results. See Figure 1. The inflection point as described above was calculated as 42 years. Conclusions. Our data indicates that the age at which diastolic BP begins to fall occurs much earlier than is generally accepted. In fact 13 years sooner than indicated by the Framingham data. The reasons for this difference are unknown at this time but could be related to the fact that the Framingham data is a population based community study and our population are patients referred for investigation of suspected hypertension, suspected white coat hypertension or assessment of hypertension control. It is possible that increased arterial stiffness may be occurring earlier in our predominantly hypertensive population than in the general Framingham population, many of whom were normotensive.